This invention relates to video editing and, more particularly, to a system involving apparatus and methodology for preparing a color master video tape in such a way that it becomes video self-editing when subsequently played across to a video recorder.
In the last few years, there has been a great growth in the development of home video recording and editing. Domestic users of home video equipment often desire to edit initial or "master" video tapes so as to delete scenes from them or to provide a rearrangement of scenes which will produce a more desirable tape. For example, a home video recording enthusiast may, after having recorded an initial tape, prefer to edit out commercial messages or less-preferred scenes or segments. Commercial users can have the same problems.
Using a first or "master" video tape in this mode typically involves playing back a master video tape on a playback recorder while using a record or "dub" video recorder to record only those scenes which are desired on the edited tape. This may be carried out by manually starting and pausing the dub video recorder while watching the first tape as it is being played on the playback recorder. The resultant tape produced by the dub video recorder now becomes a new master tape which can be used to produce, by the connection of a video tape recorder to a first playback machine, a duplicate tape.
However, such an editing approach involves several serious limitations: Since the edited video tape is in actuality a second copy, or second-generation tape, it will when played back as a new "master" provide degraded picture quality and a diminished signal-to-noise ratio. Also, the second-copy master video tape can only be further shortened or edited with even greater loss of fidelity and degradation of its video and audio recording tracks. Also, if further edited, the second-copy master provides a third-generation copy which may for many needs be almost useless, such as when played back it may not even have sufficient signal levels for providing synchronization and stability of the playback picture. The usual method as above described for obtaining a second-copy master video tape of edited character is also disadvantageous in that if it is not satisfactory or if further editing should later be desired, one would have to go completely once more through the entire editing process with respect to the original master thereby to produce a differently-edited second-copy master version. Far more desirable would be the capability of using the original master in such a way that edited copies could be made directly from it. However, prior to the present invention, the typical amateur or non-professional person has found it difficult, if not impossible, to know which scenes are to be deleted from the original master and where such scenes are precisely to begin and end, so that repeated duplication is difficult.
An additional difficulty with the prior art approach of making a second-generation master with the use of non-professional, domestic home recording equipment arises as follows: Domestic type video recorders have an ultimate protective shutdown feature which typically causes the rotating recording head to stop rotating about five minutes after tape movement is stopped. This is to prevent the tape from being worn through by the head. In conventional editing prior to this invention, the user typically has had to shut down the recorder frequently, sometimes for protracted periods, causing the rotating head to stop. Because the recording track consists of multiple diagonal tracks or strips across the surface of the tape, any effort to join two segments together, where the recording head has stopped at the beginning or end of such a segment, will result in a large visual discontinuity upon the screen, wherein the picture may actually collapse, or partial raster occurs and even resulting sometimes in short segments wherein there is a totally blank or noise-filled screen. The resultant adjacent segments, undesirably interrupted by this cessation or collapse of the video, are quite distinct from one another, and annoying abrupt transition from scene-to-scene result.
Professional equipment does exist which can be used by professional studios and those in the television industry to make high quality second generation tapes which have an adequate signal to noise-ratio and synchronization signals of proper level for assuring a clean, noise-free playback of proper level for assuring a clean, noise-free playback of the second generation master. Professional equipment can also avoid such annoying transitions between scenes. But such equipment either is not readily available to the home video enthusiast or is so expensive as to be beyond being affordable.
The present invention, insofar as it utilizes tones recorded on the original master video tape for causing the master tape to be automatically self-editing when played from a-video playback machine across to a dub video recorder, is concerned with previous efforts to record tones upon tape. In Bixby et al U.S. Pat. No. 4,290,087, for example, there is disclosed a system for playback of segmented video information on a tape. By recording only signals of a predetermined quality on an ancillary recording medium, playback of video information from the ancillary medium will produce a coherent display on a display monitor. However, this system is primarily used to improve the frame-by-frame quality and is concerned with a commercial video editor. It is not a system for video self-editing of a master video tape.
Hanpachern U.S. Pat. No. 4,319,286, teaches a system for detecting fades in television signals to delete commercials from recorded television broadcasts. But such a system is used only for deletion of the commercials from a transmitted broadcast when utilizing a video tape recorder for making a first-generation recording of the broadcast signal. It is not useful for causing deletion of selected video segments but rather all commercials which will produce the requisite fade of the signal to which such system responds.
For sound editing, it has been known, as proposed in Kelly et al, U.S. Pat. No. 4,067,049, to store on a second-generation magnetic tape signals for insertion at selected locations of special recorded sound effects. In this way, the second generation tape can be used, in effect, to key the playing back of additional sounds as for use in a television program.
Indeed, it is concededly known that control tones can be recorded upon video tape recordings, as through the use of home video recorders, such as for providing cueing or locating marks on the video or audio channels for the purpose of marking or locating the beginning of a recorded program; just as such signals have been recorded heretofore on sound magnetic recording tape to mark the beginning of a piece of music, or its end.
But none of these disclosures of the prior art have been useful for preparing a first-generation video tape for video self-editing when subsequently played across to a video dub recorder.
Accordingly, it is an object of the present invention to provide a process of preparing a video tape for video self-editing when subsequently played across to a video recorder, in effect allowing a first generation video tape to serve as a master from which edited copies may be made directly.
A further object of the invention is the provision of such a process which is especially useful for preparing a color video tape, so that upon playing back of such video tape, a characteristic indication may be given to the user of those video segments which have been selected for duplication and those segments which have not been selected, and wherein such indication can be provided either visually or aurally, or provided both visually and aurally.
It is also an object of the invention to provide such a process which does not disturb or in any way change the video information recorded initially upon the master video tape, which does not alter or delete color signals recorded thereon, and which retains and does not interfere with audio information recorded upon such tape.
It is a further object of the invention to provide a process for pre-selected editing and subsequently duplicating only the pre-selected portions, either of a single video tape from which an edited second-generation copy is then produced by a single uninterrupted playing, or from a plurality of such pre-edited video tapes, composed in a preselected order.
It is an object of the invention also to provide apparatus for video editing capable of use with a video playback machine and a video recorder which will allow the recorder to produce an edited first-copy video tape by duplication only of preselected portions of a master video tape without interruption of the playing of the master video tape by the video playback machine.
It is a further object of the invention to provide such video editing apparatus which will provide the user with a characteristic visual indication of those portions of the tape which have been selected for duplication, and wherein such indication involves displaying on a monitor the selected portions in color and black-and-white, a related object being to provide apparatus which, during playback of the master tape, provides aural indication of the selected and unselected portions by causing the audio volume for unselected segments or portions to be diminished in volume.
Additionally, it is an object of the present invention to provide such video editing apparatus which will signal the beginning and end of a series of selected portions; and a related object is to provide such apparatus which automatically will respectively enable and disable editing functions of the apparatus at the beginning and end of a series of selected portions.
It is also an object of the invention to provide such video editing apparatus which can be used not only for preparing a video tape for video self-editing, but also for thereafter causing the tape to be self-editing when played across to a video recorder, as well as for providing characteristic indication to the user by monitor display of the selected and unselected portions of the tape so prepared.
It is an object of the invention to provide such a process and apparatus which allow preparing of the video tape which not only has the capability of being self-editing for producing a first copy of only selected video signals of the tape, but also retaining a capability for being subsequently changed whereby it can provide for subsequent self-editing production of a first copy of different selected portions.
Among other objects of the invention may be noted the provision of such apparatus which avoids the objectionable starting and stopping of the recording head of a dub video recorder connected to it, thereby preventing objectional gaps or discontinuities between scenes of the edited tape copy.
Briefly, video editing apparatus of the invention is used with a conventional video playback machine, such as a first VCR, and a dub video recorder, such as a second VCR. The apparatus includes tone generator means for generating an edit tone to be recorded upon an audio track of a master video tape which has been preselected for edit duplication. Control means is included for selectively supplying the edit tone to the playback machine for recording upon the audio track to differentiate selected from unselected portions of the video track of the tape. The apparatus includes tone decoder means for decoding the recorded edit tone upon playback of the master tape. Dub video recorder control means is provided for controlling starting and stopping of the dub video recorder in response to the decoded presence or absence of the recorded edit tone, as determined by the tone decoder means. Accordingly, the dub video recorder when connected to the playback machine will produce an edited first copy video tape by duplication only of the selected portions of the master video tape, and without interruption of the playing of the master video tape. According to the preferred construction, a video monitor is used for receiving and viewing the video signals from the playback machine, the apparatus including further control means responsive to decoding of the edit tone for causing the video monitor to delete color during playback of the unselected portions of the master video tape. The apparatus may also include circuitry for causing diminished audio volume of the signals provided to the video monitor during playing back of the unselected tape portions.
A process of preparing a color video tape for self-editing according to the invention involves the steps of (1) playing an initial portion of the tape on the playback machine while simultaneously viewing same on the color video monitor to the conclusion of a first segment or portion selected for such subsequent duplication; (2) while so playing and viewing, laying down on an audio track of the video tape signals to differentiate portions of the tape selected for duplication from unselected portions thereof, and to start and stop the dub video recorder; (3) so controlling, by the presence or absence of said signals, the video input to the monitor so as to delete color from such video input simultaneously with the display of unselected portions of the video tape; and (4) repeating the aforesaid steps for subsequent portions of the tape. Accordingly, by adjusting the position of such recorded signals as laid down on the audio track, the absence of color on the monitor screen indicates the portions which will be self-edited from the tape when thereafter played across to the dub video recorder.
Other objects and features will be in part apparent and in part pointed out hereinbelow.